Save jpeg o targa file from unreal of uvmps on chanel 0

I need a jpeg o targa file of the uvmaps on chanel 0 in Edit mesh to make texture with photoshop.

I import from 3ds with correct lightmaps on chanel 1. With 3ds i can save a targa file of this uvmap. But in edit mesh in unreal the chanel 0 is different from chanel 1.
Actually in edit mesh i click on the uv button on the top, move the camera on a grey space ad take a screen shot… The result is awful

There is another method to do this?
Or there is a way to have the same uvmaps on chanel 1 and 0?

Sorry for my english and thx for all.